1 THE GECAFS Scenario Workshop

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Environmental Scenario AnalysisOverview and
Approaches

• Thomas Henrichs
• European Environment Agency

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Overview Approaches ...

• Definitions of scenarios
• Elements of scenarios
• Goals of scenarios
• Types of scenarios
• How may scenarios
• Developing Analysing scenarios
• Good scenarios

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Many different definitions exist ...

• A scenario is a sequence of events especially
  when imagined especially an account or
  synopsis of a possible course of action or
  events. (Merriam-Webster Dictionary
  On-line, 2003)
• Scenarios are hypothethical sequences of events
  constructed for the purpose of focussing
  attention on causal processes and decision
  points. (Kahn and Wiener, 1967)
• Scenarios are descriptions of journeys to
  possible futures. They reflect different
  assumptions about how current trends will unfold,
  how critical uncertainties will play out and what
  new factors will come into play.
  (UNEP, 2002)

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Definition of scenarios (EEA)

• scenario
• a plausible description of how the future may
  unfold based on a set of 'if-then' propositions.
• A typical environmental scenario includes a
  representation of the initial situation and a
  storyline that describes the key driving forces
  and the changes that lead to an image of the
  future. Note that scenarios are neither
  predictions nor forecasts.

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Elements of scenarios

• Current State
• situation in the base year of scenario
• Driving forces
• deteminants that influence changes
• choices/decisions that bring changes
• (Step-wise) Changes
• at the core of a scenario analysis
• depicting how the driving forces unfold
• storyline highlighting key features
• Image(s) of the future
• situation in the end year of scenario

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Types of environmental scenarios

• Exploratory vs Anticipatory Scenarios
• exploratory scenarios
• present -gt future
• to explore uncertainties/driving
  forces/developments
• to test impacts of implementing specific policies
• antipatory scenarios (also normative scenarios)
• present lt- future
• to investigate how specific end state can be
  reached
• to show how to achieve environmental targets

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Types of environmental scenarios

• Baseline vs Alternative Scenarios
• baseline scenarios (also reference scenarios)
• describe a future development / state in which
  no new policies or measures are implemented
  apart from those already adopted or agreed upon
• alternative scenarios (also policy scenarios)
• take into account new policies or measures
  additional to those already adopted or agreed
  upon and/or that assumptions on key driving
  forces diverge from those depicted in a baseline
  scenario

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Types of environmental scenarios

• Qualitative vs Quantitative Scenarios
• qualitative scenarios
• are narrative descriptions of future developments
• (i.e. presented as storylines, diagrams, images,
  etc.)
• quantitative scenarios
• are numerical estimates of future developments
• (i.e. presented as tables, graphs, maps, etc.)
• usually based on available data, past trends
  and/or mathematical models

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Goals of environmental scenarios

• Education / Public Information
• to educate and teach students, citizens, pupils
• to raise awareness of policy-makers, stakeholders
• Science / Research
• to integrate information from different fields
• to explore possible developments
• Strategic Planning / Decision Support
• to gather different views and to identify issues
• to frame strategic issues, to identify
  alternatives
• to support policy measure development

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How many scenarios?

• As many as possible
• to represent the many views of the future
• to represent the many options of the future
• As few as necessary
• to avoid scenario fatigue
• to make the process handable
• Large projects with complex scenarios often aim
  for 2 to 4 scenarios

Based on EEA (2001)
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Combining approaches
Story-and-Simulation
Quant. Scen.
Data Modelling Group(s)
Based on EEA (2001)
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GlobalLocal level integration

• Option 1Develop global and local scenarios in
  parallel / iteratively

Global-Level Scenarios
Regional-level Scenarios
Level of Detail
Local-level Scenarios
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What are good scenarios?

• Good scenarios should ...
• ... be plausible (or not implausible)
• ... be internally consistent and coherent
• ... be constructed with rigour, detail
  creativity
• ... meet the goals of scenario exercise!!!

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EEA environmental scenarios portal

• Web Portal
• EEA Reports
• Links to
• institutions
• networks
• studies
• Resources
• News
• Glossary
• Bibliography

• http//scenarios.ewindows.eu.org

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